Voltammetric Sensors and Sensor System Based on Gold Electrodes Modified with Polyarylenephthalides for Cysteine Recognition

Voltammetric sensors and a sensor system based on gold electrodes modified with polyarylenephthalides (chlorinated polyphthalidylidene fluorene and polyphthalidylidene diphenyl and brominated polyphthalidylidene diphenyl) for the identification of cysteine are developed. The surface morphology of the modified electrodes and electrochemical and analytical characteristics of the sensors are studied, the conditions for the electrochemical oxidation of cysteine and the production of an analytical signal are optimized. The proposed sensors and sensor system, with chemometric processing of response signals, allows recognizing manufacturers of cysteine-containing pharmaceutical preparations. The use of the voltammetric sensor system can significantly increase the percentage of correctly recognized samples in comparison with the registration of voltammograms on separate electrodes.